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Topic 3: Network Security

Network security in the cloud is about building secure connections, creating logical separations between resources, and defending against network-based threats. Before securing your Journal API's network, you need to understand cloud networking fundamentals.

Learning Objectives​

By the end of this topic, you will understand:

  • Virtual Private Clouds (VPCs) and network isolation
  • Security Groups vs Network ACLs and when to use each
  • Load balancers and secure traffic management
  • VPN and private connectivity options
  • Common network security mistakes and how to avoid them

Core Learning Resources​

1. Read: Cloud Networking Fundamentals​

Start with your cloud provider's networking documentation:

AWS: VPC User Guide - Read sections on VPCs, subnets, and security groups Azure: Virtual Network Overview - Read concepts and security features GCP: VPC Network Overview - Read VPC concepts and security

2. Watch: Network Security in Action​

3. Learn: Network Security Best Practices​

Key Concepts to Master​

Virtual Private Clouds (VPCs)​

  • Isolation: Your own private network in the cloud
  • Subnets: Divide your VPC into smaller network segments
  • Route Tables: Control where network traffic can go
  • Internet Gateways: Allow internet access where needed

Security Groups vs Network ACLs​

Security Groups (Stateful):

  • Act like firewalls for individual instances
  • Allow rules only (deny by default)
  • Stateful (return traffic automatically allowed)
  • Apply at the instance level

Network ACLs (Stateless):

  • Act like firewalls for entire subnets
  • Allow and deny rules
  • Stateless (must explicitly allow return traffic)
  • Apply at the subnet level

Network Segmentation​

  • Public Subnets: For resources that need internet access (load balancers)
  • Private Subnets: For application servers and databases
  • Isolated Subnets: For highly sensitive resources with no internet access

Load Balancers and Traffic Management​

  • Application Load Balancers: Handle HTTP/HTTPS traffic with security features
  • Network Load Balancers: Handle TCP/UDP traffic at high performance
  • Security Features: SSL termination, DDoS protection, access logging

Test Your Knowledge​

Use an AI assistant to test your understanding. Here are example prompts:

  1. "Quiz me on the difference between Security Groups and Network ACLs"
  2. "Ask me to explain VPC concepts like subnets and route tables"
  3. "Test my knowledge of when to use public vs private subnets"
  4. "Quiz me on load balancer types and their security features"
  5. "Ask me about network segmentation best practices"
  6. "Test my understanding of stateful vs stateless firewalls"
  7. "Quiz me on VPN types and when to use them"
  8. "Ask me about common network security mistakes in the cloud"

Physical vs Cloud Network Security​

Understanding the differences helps bridge the conceptual gap:

Physical Network ComponentsCloud EquivalentsKey Differences
Physical routers and switchesVirtual routers, VPC gatewaysSoftware-defined networking via console/API
Hardware firewallsSecurity Groups, NACLsRules applied through cloud interfaces
Physical network segmentationSubnets, VPCs, Security GroupsLogical boundaries replace physical ones
Network cablesVirtual connections, peeringNo physical connections to manage

Additional Resources (Optional)​

Cloud Provider Documentation​

Network Security Tools​

Practice Resources​

Next Steps​

Once you feel confident with network security concepts, move on to Topic 4.